Background: The appropriateness of new consumer-directed health plan (CDHP) benefit designs for people with chronic illnesses has been questioned, but little information exists regarding the experience of chronically ill individuals in CDHPs. To contribute to a better understanding of the experience of people with chronic illnesses in CDHPs, this study analyzed survey and medical claims data from a large public employer that offered a CDHP as well as other benefit options. Methods: An analysis of combined survey, administrative records, and medical claims data was conducted for a sample of employees participating in a large public employer's health benefits plan. The main outcome measures were plan enrollment decision, use of information, plan rating, and spending patterns. Results: Employees with chronic illness are equally likely as other employees to join a CDHP, to understand key plan coverage features, and to report having a particularly positive or negative experience with their plan. However, CDHP enrollees with chronic illnesses assign higher ratings to their plan than do other CDHP enrollees (p < 0.07). They are more likely than other CDHP enrollees to use informational tools (p < 0.05), more likely to anticipate spending all of their savings account dollars (p < 0.05), and more likely actually to spend more than the deductible (particularly for prescription drug expenditures [p < 0.05]). Compared with other CDHP enrollees whose spending exceeds the deductible, enrollees with chronic illnesses spend significantly more on prescription drugs. Conclusions: Even though the CDHP benefit design was generous, relatively few employees chose the CDHP, and the CDHP was no more attractive to employees with chronic illnesses than to other employees. Furthermore, although people with chronic illnesses who chose CDHPs had some understanding of how their health savings accounts (HSAs) would work, they tended to exhaust those accounts and also spend more than the plan's deductible. There is much more for employers to do if they want CHDP enrollees with chronic illnesses to 'manage' their conditions more effectively.